i have a lead on a fix for this. i think it may be (at least in part) due to incorrect handling of tile rotation- possibly it ends up with rotation values outside of the 0-4 range (which is fine internally, but won't save correctly). i'm looking into this right now actually, and i'll upload the fix tonight. i sincerely hope that will address all of the save corruption issues. that's such a tragic bug; by far the worst bug on the list. fixing that is my highest priority right now.